Fluid clutch



March 13, 1945. A, Y. DODGE FLUID CLUTCH Filed Nov. 26, 1941 PatentedMar. 13, 1945 `UNI-TED STATES PATENT OFFICE i l 2,371,227

FLUID CLUTCH Adiel'Y.Dodge, Rockford, Application November 26, 1941,serial No. 420,479 s claims. (ci. 1oz-c1) This invention relates tofluid clutches and more particularly to positive displacement type iluidclutches controllable to connect or discon- -nect two shafts. Y

One of the objects of the invention is to prof vide a fluid clutch whichcomprises essentially a simple gear set and a simple control valve.

l A clutch of this character is inexpensive to construct, butis highlyeifective in action and can be connected or disconnected under fullload.

Another object of the invention is to provide a fluid clutch includinginter-acting fluid displacement parts coaxial with each other and with Athe driving and driven shafts.

Another object of the linvention is to provide a iluid clutch in whichthe control valve is coaxial with the driving and driven shafts and isslidable axiallylthereof to control the clutch operation.

Still another object of the invention is to provide^a iluid clutch ofthe planetary gear type in which inletl and outlet portsare formed inthe sides of the planetcarrier and communicate with the ends of the gearteeth. Preferablyfthe inlet and outlet ports are at opposite ends of thegears together, the center ring being formed with an internal gear 1.The gear 'I meshes with a series of planet gears 8, rotatably carriedbetween end plates 9 and I I, and the gears 8 in turn mesh with a sungear l2 carried by the shaft 4.

The end plates 9 and II of the planet carrier.

ttightly against the ends of the gear teeth to seal them againstfluidleakage, and spacer members I3, as shown in Figures 2 and 3, arearrangedbetween the gears and engage the ends of the teeth. The endplates 9 and II are rigidly secured together by bolts extending into theblocks I3 as shown to form a unitary gear carrier for the planet gears 8which is rotatable relative to the ring gear 1 and sun gear I2. Thegears thus form a positive displacement gear pump of a type known in theart.

' Inlet passagesfor the gear pump are'provided by radially extendingchannels I4 in the plate II, opening at the radial inner edge of saidplate, and terminating inlet ports -I5 rspaced substantiallydiametrically of the planet gears k8 at the points where the planetgears mesh with I the ring gear I and sun gear I2. It will be noted sothat `the iluid ilows completely across the gears.

Another object of the invention is to provide a fluid clutch of theplanetary gear type in which .two inlet and two outlet ports areprovided for .each planet gear. This construction provides a doublepumping action, increasing the capacity of the unit for a given size. v

Another object of the invention is to provide `a fluid clutch of theplanetary gear type in which the diierent elements at different radiiare made use of to reduce 'the fluid pressure required by reducing thetooth load.

, Yet another object is to provide a fluid displacement clutch in whicha' minimum now of nuid is maintained at all times for the purpose oflubrication. l

The above and other objects and advantages of the invention will beapparent from the following description when read the accompanyingdrawing, in which:

Figure l is an axial section of ing' the invention; and

Figures 2 and 3 are sections on the lines 2-2 and l--l respectively ofFigure 1.

'I'he clutch shown `in Figure 1 is adapted to connect two shafts, 4 and5. one of which may be the driving and the'other the driven shaft.. Theshaft I is connected to a casing which is made in connection with aclutch embodyup ot end plates Ia and a center ring 5b bolted 55 thatthere are two inlet ports for each planet gear, so that each side of thegearoperates as a separate gear pump. 2

. Outlet ports for the pump are provided by similar radially extendingchannels I6 in the plate 9, opening at the radial inner edge of theplate and terminating in spaced outlet ports Il, spaced substantiallydiametrically of the planet gears 8. It will lbe noted that there aretwo outlet ports for each planet gear adjacent the points at which theplanet gears engage the sun and ring gears, and oiset with respect tothe inlet ports.

To facilitate formation of the channels Il and I6 the plates 8 and IIare each preferably formed of two plates secured together with facegrooves cut in one of the plates to for-m the channels.l

,Fluid is supplied to the unit through the inlet passages I4 from acentral fluid chamber I8,

formed in an extension of the shaft 4 and coaxial with the shafts. Fluidenters the cha'mber I8 through ports I9 'and flows therefrom'into theinlet passages through radial ports 2I in the shaft extension. Fluidleaving the pumpthrogh the outlet passages I6 ,ilows back into thecentral chamber through similar radial ports 22 in the shaft extension.

Flow of fluid through the passages'is controlled by a valve member- 23.slidably fitting in the uid :chamber I8, whichv is preferablycylindrical and controlled by a valve rod 24 extend- 26 into register.

'ing through the shaft 5. IThe valve member 23 lits tightly against thewalls of the fluid chamber so as to control the ports`2l by itsposition. The valvel is formed with a bore, as at 25, communicating atone end with ports 28 adapted to register with the ports 22, and at itsopposite end through openings 21 in a closure plug 28 with the inlet endof the chamber i5. The passage 25 is normally closed by a valve 29,urged against its seat by a spring 3l, and lo adapted to open under apredetermined pressure.

With the valve in the position shown in Figure 1, the shafts 4 `and 5are disconnected. Inl

this position the inlet ports 2l are closed and the outlet ports 22 areopen around the valve stem 24'; any fluid contained in the gear pump atthis time will be forced out through the ports 22 and around the rod 24,anii/ may be removed from the casing in any desired manner. Thus theiluid passages between the gear teeth are empty and the several gearelements may rotate freely relative to each other.

In order that the parts may be properly lubri-l a small amount of fluidfrom the bore 25 to the pump inlets and insures that the pump 'will belubricated properly at all times. I

When the valve 23 isshifted to. the left,q it opens the ports 2| andbrings the ports 22 and At this time uid is admitted and is forcedtherethrough by to the gear pump if there is any relative operation ofthe gears ,rotation between the shafts 4 and 5. The fluid is forced out'through the outlet ports under pressure, and through the ports 22 and26 into the bore 25. If the pressure is large enough to unseat the valve29, the iiuid flows through the bore 25 and by-passes back to the inletports through ports 2l. It will be understood that the tension of spring3l valve 29 will open at any desired pressure, this construction formingan overload release 'to prevent damage to the parts and to limit theamount of torquewhich can be transmitted by the clutch. Resistance toflow of fluid through the outlet ports tends to resist relative rotationof the gears, so that torque will be transmitted between the shafts 4and 5, whereby one of the shafts may drive the other. In normaloperation, when the load is less than that for which the valve 29 isadjusted, the vduid will prevent anysubstantial relative rotationbetween the gears. thereby locking the gear unit so that the shafts 4and 5 and the gear carrier formed by parts 9,. and i3 will operate atsubstantially the samespeedandinthesamedirection.`

The clutch of the present invention is particularly adapted for use inconnection with trons of the type illustrated in my copendingaPPIicatiOIlS. Serial No. 416,319, died October 24, 1941, and Serial No.419,883, filed November 21, 1941. In an environment such as that shownin these applications, it may be desirable to prevent overrunning of oneof the shaftsrelative to the other. as for example, to'

es i4 may lntercommuni- 3 way clutch `and bearing n, which may be or thetype more particularly disclosed and claimed in either my Patent No.2,268,376 or my copending application, Serial No. 406,137 filed August9, 1941. For example, if the shaft 4 is considered as a driving shaft,the clutch would be so a1'- ranged as to permit shaft 4 to turnforwardly faster than shaft 5, but to prevent shaft 5 from turningforwardly faster than shaft 4.

Under certain operating conditions, as for example, when heavy torqueloads are to be transmitted at relatively low speeds, advantage may betaken of the different effective radii to reduce the tooth loads and thenuid pressure required to transmit a given torque. For this purpose. thegear carrier formed by plates 2 and Il may be connected to a sleeveshaft I4 surrounding the shaft 4 and connected tothe plate il byinterengaging the teeth to form a permanent driving connection. Drive istransmitted between the shaft 5 and the sleeve shaft I4 and the shaft 4and sun gear l2 are permitted to idle.

With the unit connected in this manner, relative rotation between theshafts 5 and 54 with .ring gear 1 turning relative to the carrier in thedirection of the arrow in Figures 2 and 3 'causes relatively rapidrotation of the gears about their own axes due to direct meshing of thering gear and planet gears to cause increased speed of the sun gear,resulting in a high tooth speed and low toothV load. When the inletvalve is opened, the gears thus tend to pump larger volume of fluid atlower pressure, so that less fluid pressure on the vvalve and gearelements is produced to transmit a given torque than when a shafts 4 ands are utuized as the 10aa shafts.

While one embodiment of the invention has been shown and described indetail, it will be understood that this is illustrative only. and islnot to be taken 'as a definition of the scope of o the invention,reference being had for this pur` pose to the appended claims.

What is claimed is: l. A uid clutch comprising a rotatable planetcarrier member, planet gears rotatably mounted on the carrier member,sun and ring gear memmaybeadlustedsothatbers meshing with the planetgears, means closing the spaces between the gears, two of saidmembersbeing connected respectively to driving driven shafts, meansforming inlet and outlet passages for fluid in the planet carrieropening at the sides of the gears, and valvemeans to control the flow offluid through both said inlet and outlet passages.

2. A fluid clutch comprising .a rotatable planet carrier member, planetgears rotatably mounted on the carrier member, sun and ring 'gearmembers meshing with the planet gears, means closing the spaces betweenthe gears, two of said members being connected respectively to drivingand drivenshafts, means forming inlet and outlet passages for iiuid inthe planetcarrier opening at the sides of the gears, a valve to controlinlet of -fluid through the inlet passage, means :forming4 a by-passbetween the outlet and inlet passages, and a pressure responsive valvenormally closing the by-pass.

a. A uuid clutch comprising a. rtatabie planet carrier member, planetgearsl rotatably mounted on the carrier member, sun and ring gearmembers meshing with the planet gears, means closing the spaces betweenthe gears, two of said members being connected respectively to thedriving and driven shafts, said planet carrier\ substantially radialpassage in the sides carrier member, planet gearsrotatably mounted onthe carrier member, sun and ring gear members meshingwith the planetgears, meansclosing the spaces between the gears, two of said membersbeing connected respectively to driving and driven shafts, said planetcarrier having substantially radial passage in the sides thereofterminating in inlet and outlet openings at the sides of the gears,means forming av fluid chamber coaxial with theclutch, a valvecontrolling communication of the chamber with the inlet passages, and arelief valve controlling communication of the chamber with the outletpassages'.

5. A fluid clutch for connecting coaxial driving and driven shaftscomprising a casing coaxial with the shafts,members in the casinginterengaging to form a positive displacement pump, the casing beingformed with radially extending inlet and outlet passages for the pump,means forming a fluid chamber kcoaxial with the shafts radially inwardof the members, and a valve slidable axially in said chamber to controlthe flow of fluid through the passages.

6. A fluid clutch for connecting coaxial driving and driven shaftscomprising a casing coaxial with the shafts. members in the casinginterengaging to forma positive displacement pump. the casing beingformed with radially extending inlet and outlet passages for the pump,means forming a fluid chamber coaxial with the shafts, a valve slidableaxially in the chamber to control communication between the chamber andthe inlet passages, said valve having an opening therethrough connectingthe inlet and outlet passages, and a pressure responsive relief valvenormally closing said opening. K

'7. A uid clutch comprising relatively rotatable members forming apositive fluid displacement unit having inlet and outlet passages, avalve controllingsaid passages to close the inlet' and open the outletor to open the inlet and close. the outlet, the valve having meansassociated therewith to provide a minimum opening for fluid to the inletpassage when the valve is in a position to close the inlet passage toprovide a minimum amount of fluid through said members for lubrication.Y.

8. A fluid clutch comprising a planetary gear set having means enclosingthe gears to form a positive fluid displacement unit and having inlet iand outlet passages, a valve controlling said pasy sages to close theinlet and open the outlet or .to open the inlet and close the outlet,theV valve having means associated therewith to provide a minimumopening for fluidto the inlet passage when the valve is in a. positionto close the inlet passage to provide a minimum amount of ilui throughthe gears for lubrication.

ADIEL Y. DODGE.

